In entries in the reference list:


1. periods are used to separate major elements (e.g. names of authors, dates, titles).


2. a comma is used to separate the name of a periodical from volume and page number information.


3. brackets are used to indicate nonruoutine information that is important for identification and retrieval.


4. punctuation may vary in format according to the type of source.


5. all of the above are correct